The Shure 940 would be a good match from the upper midrange to the low bass. But the 940 will probably sound slightly brighter, which can be fixed the way I describe in my Youtube video of the Shure 1440. The 940 is fairly neutral like the Senn's but more detailed, and the ear pieces and pads and the way they fit are very similar to the Senn's. The 940 also has an unusual spaciousness and soundstage for a closed headphone. One thing I also like about the 940 is the portability - although the carrycase is too large for baggage, the earcups pull down far enough and fold flat so I can wear it around my neck all day without it getting in my way.

i wish i was articulate enough to say just what it is about my 650s i love so much, when i purchased them from a little local dealer who sadly is no longer trading i auditioned them against grado RS-2s.

The grado probably had a clearer sound to my ear, but there is something towards the bottom end that made the Senheisers more comfortable to me. I do listen to music for hours each day with them.

its between 3 now i think, and ill put them in order that im thinking.

You would probably really like the Ultrasone Pro 900. Very solid sounding - much tidier bass than the HD650 and a little more grasp of fine detail. They do take some driving though, it's still a comfortable sound which is quite warm, not cold and harsh as some Pro headphones can feel. GMP 450 are a similar affair, very nice neat bottom end considering it is strong - more texture than the HD650. Both are a slightly less comfortable listen but I feel it is an improvement over the HD650 which feel a little lazy to me, although they are great cans if you like a very relaxed sound. GMP 450 are also feather light and very comfy, Pro 900 is not heavy at all - all three are very comfy really. Also they all benefit from a detailed and powerful amp.